package com.a2.appa3.util;

/**
 * Created by admin on 2019/1/1.
 */

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

/**
 * Created by wanglingsheng on 2018/5/29.
 * 文件下载工具类（单例模式）
 */

public class DownloadUtil {

    private static DownloadUtil downloadUtil;
    private final OkHttpClient okHttpClient;

    public static DownloadUtil get() {
        if (downloadUtil == null) {
            downloadUtil = new DownloadUtil();
        }
        return downloadUtil;
    }

    public DownloadUtil() {
        okHttpClient = new OkHttpClient();
    }


    /**
     * @param url          下载连接
     * @param destFileDir  下载的文件储存目录
     * @param destFileName 下载文件名称
     * @param listener     下载监听
     */

    public void download(final String url, final String destFileDir, final String destFileName, final OnDownloadListener listener) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                Request request = new Request.Builder()
                        .url(url)
                        .build();

                OkHttpClient client = new OkHttpClient();

                try {
                    Response response = client.newCall(request).execute();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                //异步请求
                okHttpClient.newCall(request).enqueue(new Callback() {
                    @Override
                    public void onFailure(Call call, IOException e) {
                        // 下载失败监听回调
                        listener.onDownloadFailed(e);
                    }

                    @Override
                    public void onResponse(Call call, Response response) throws IOException {
                        InputStream is = null;
                        byte[] buf = new byte[2048];
                        int len = 0;
                        FileOutputStream fos = null;
                        //储存下载文件的目录
                        File dir = new File(destFileDir);
                        if (!dir.exists()) {
                            dir.mkdirs();
                        }
                        File file = new File(dir, destFileName);
                        try {

                            is = response.body().byteStream();
                            long total = response.body().contentLength();
                            fos = new FileOutputStream(file);
                            long sum = 0;
                            while ((len = is.read(buf)) != -1) {
                                fos.write(buf, 0, len);
                                sum += len;
                                int progress = (int) (sum * 1.0f / total * 100);
                                //下载中更新进度条
                                listener.onDownloading(progress);
                            }
                            fos.flush();
                            //下载完成
                            listener.onDownloadSuccess(file);
                        } catch (Exception e) {
                            listener.onDownloadFailed(e);
                        } finally {

                            try {
                                if (is != null) {
                                    is.close();
                                }
                                if (fos != null) {
                                    fos.close();
                                }
                            } catch (IOException e) {

                            }

                        }


                    }
                });
            }
        }).start();
    }


    public interface OnDownloadListener {

        /**
         * 下载成功之后的文件
         */
        void onDownloadSuccess(File file);

        /**
         * 下载进度
         */
        void onDownloading(int progress);

        /**
         * 下载异常信息
         */

        void onDownloadFailed(Exception e);
    }
}

